<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    .box {
        position: relative;
        width: 400px;
        border-bottom: 1px solid #ccc;
        margin: 100px auto;
    }
    .box input {
        width: 370px;
        height: 30px;
        border: 0px;
        outline:none;
    }
    .box img{
        position: absolute;
        top: 1px;
        right: 1px;
        width:24px;
    }
</style>
<body>
    <div class="box">
        <label for=""><img src="images/close.png" alt="" id="eye"></label>
        <input type="password" name="" id="pwd">
    </div>
    <script>
        var eye = document.getElementById('eye');
        var pwd = document.getElementById('pwd');
        var flag = 0;
        eye.onclick = function() {
            if(flag == 0) {
                pwd.type ='text';
                eye.src = 'images/open.png';
                flag = 1;
            }else {
                pwd.type = 'password';
                eye.src = 'images/close.png';
                flag = 0;
            }
        }

    </script>
</body>
</html>